1. Field of the Invention
The present invention relates to a device useful for adjusting the height at which a load is supported by an upright column relative to an underlying surface, and has particular utility for leveling construction scaffolding and for supporting tools and lengthy stock to be machined.
2. Description of the Prior Art
Conventional scaffolding typically involves the use of specially designed scaffold supporting structures that are utilized for only one purpose, which is the support of scaffolding planks. Conventional scaffolding components are bulky, heavy and require significant transportation and storage expenses. As a consequence, most contractors that require the use of scaffolds simply have insufficient storage space to keep the scaffolding when it is not is use. Also, due to the bulky and unwieldy nature of many of the components, many users of scaffolding do not have the proper type of vehicles for transporting the scaffolding units, even if they have a place to store them. As a consequence, most contractors and other entities that require scaffolding are forced to rent the scaffolding components that they need each time they require scaffolding for a construction job. The rental, erection, and dismantling of scaffolding therefore represents a very significant expense to construction workers, pipe fitters, and other tradesmen that require the use of scaffolds.
A primary object of the present invention is to provide a system for adjusting the height at which a load is supported by an upright column above an underlying surface that does not require lengthy, bulky, special purpose equipment. To the contrary, the present invention involves the use of relatively small, unique fittings and devices which can be utilized with lengths of general purpose pipe or steel rods to create the necessary height adjustment and load leveling support required to perform a particular job. The fittings and couplings employed in the present invention are adaptable for use on general purpose, hollow, steel pipes that are bought in bulk and sold widely for a multitude of different purposes. Furthermore, the pipes that are used to create the scaffolding and other load-supporting, height-adjusting structures is often ultimately utilized on the job, and thus does not require storage.
The use of the set of fittings and couplings according to the invention is not limited to the construction of scaffolding. Quite to the contrary, the load-supporting, height-adjusting devices of the invention are also very useful for supporting and adjusting the height of lengthy articles of stock, such as pipe, gutter stock, lumber, and numerous other lengthy and unwieldy articles which must be supported in a level manner.
The invention is also quite useful as a means for mounting power tools or manually operated tools, since the elevation-adjusting system of the present invention can be fine tuned to a remarkable degree. That is, the support of large, lengthy and bulky loads can be leveled with great precision utilizing the load-supporting system of the invention.
The coupling and fitting components employed according to the invention may be readily disassembled from the pipe stock or rod stock with which they are utilized to conserve room to facilitate shipment and storage of the coupling and fitting members of the invention. When a load-supporting system employing the components of the invention is required, the user simply arranges for the delivery of general purpose pipes or steel rods to the job site, while bringing the unique coupling and fitting members of the invention independently of the lengthy pipe or rod stock that is necessary. The user then simply cuts the stock to the appropriate length at the job site and, in most applications, ultimately utilizes the pipe stock or rod stock for some other purpose once there is no longer a requirement for the load-supporting system of the invention.
In a typical application, a contractor or pipe fitter will order in bulk an appropriate quantity of pipe, such as Schedule 40 steel black pipe, typically between one and two inches in outer diameter. Pipe stock of this type can be purchased at most hardware stores or steel dealers.
If the user has a particular requirement for a tool mount, the user will normally create a load-engaging adapter so that the particular tool or heavy device that the user wishes to support may be engaged by the adapter and supported from beneath by a straight, externally threaded, cylindrical structure which is provided as one of the fitting elements of the invention. That is, the user will typically weld a load-engaging adapter suitable to mount the particular tool involved onto a plate, bracket, support table, or other type of structure forming part of the tool. The user then mounts the tool onto a column provided according to the invention. Once the mounting structure has been joined to the vertically oriented steel rod or pipe, the tool involved is integrated into the load-supporting system of the invention.
The principal unique feature of the invention resides in the novel manner of adjusting the longitudinal position of an upright, load-bearing column relative to a sleeve through which the column passes. In this connection a longitudinally extending appendage is provided on the sleeve to extend longitudinally therefrom at a spaced distance from an upright pipe or rod mounted within the sleeve. This appendage is located outboard of the column and defines a jaw facing the column axis. The appendage is provided with a jaw that faces the pipe or rod supported within the upright sleeve. The jaw is formed with a horizontal radial ledge longitudinally remote from the closest end of the sleeve, and an inclined, wedging or jamming surface that extends from the ledge both radially inwardly and longitudinally toward the end of the sleeve at which the appendage is mounted. The jaw is configured so that the periphery of a strong, flat, annular washer will fit into the jaw when the washer is positioned about the column to be supported. The opening through the washer is only slightly greater than the diameter of the column to be supported, and the periphery of the washer extends into the jaw of the appendage which may project either up or down from the sleeve to which the appendage is attached.
When the washer is oriented perfectly perpendicular to the alignment of the column, relative longitudinal movement between the washer and the column occurs easily. The column can move through the washer opening and through the passageway in the sleeve to which the appendage is attached. However, the application of a load from above to the column will cause the peripheral edge of the washer to bear against the wedging or jamming surface of the appendage, thus tilting the washer out of perpendicular, coaxial alignment with the column. When this occurs, the circular, interior edge of the washer at the washer opening jams against the outer surface of the column and prevents further downward, longitudinal movement of the column relative to the surrounding sleeve or the sleeve relative to the column. The column is thus lodged in a specific longitudinal relationship relative to the sleeve.
For safety purposes, the sleeve is preferably provided with a radial opening that receives a radially inwardly directed set screw or clamping screw. This radial opening in the wall of the sleeve may itself be threaded, but in preferred embodiments of the invention a heavy-duty threaded nut is externally mounted and welded to the outside surface of the sleeve in alignment with the radial opening in the sleeve wall. The use of an external nut provides greater security in engagement of the clamping screw or set screw relative to the sleeve.
In one broad aspect the present invention may be considered to be a device for adjusting the height above an underlying surface at which a vertical column of uniform outer cross-sectional area and having a longitudinal axis of alignment supports a load. The device is comprised of a hollow sleeve, an outboard longitudinal extension from the sleeve and a jamming plate, which is typically a heavy-duty flat steel washer.
The hollow sleeve defines an enclosed passageway therethrough that conforms in shape to the outer cross-sectional area of the column so that the sleeve is disposed coaxially about the column in sliding relationship therewith. The outboard longitudinal extension from the sleeve is spaced outwardly from the column and defines a jaw directed toward the axis of alignment. The jaw is formed with a horizontal ledge having proximal and remote ends relative to the longitudinal axis, and a jamming surface that extends from the remote end of the jaw both longitudinally toward the sleeve and inwardly toward the axis of alignment.
The jamming plate has a laterally enclosed opening therethrough encompassing the vertical column therewithin. The jamming plate has a peripheral edge that projects into the jaw between the ledge and the jamming surface thereof. The jamming plate is movable longitudinally along the column when it is perpendicular to the longitudinal axis of the column. On the other hand, the jamming plate jams against the outer surface of the column when forced out of perpendicular alignment relative to the axis of column alignment.
The jaw includes a radial ledge located remote from the sleeve and the wedging surface is angled toward the sleeve and toward the column. The flat, annular jamming plate is disposed about the column and has a periphery that extends into the jaw. When the jamming plate is oriented perpendicular to the column, it is possible to longitudinally adjust the relative position of the sleeve and the column. One of the two components, either the sleeve or the column, is coupled to the load bearing down from above, while the other of these components is supported from a stand located upon an underlying surface above which the load is to be supported.
The invention may be described with greater clarity and particularity with reference to the accompanying drawings.